Combination approach for CDC73-related parathyroid carcinoma in an adolescent female patient: a case report and literature review.

Parathyroid carcinoma (PC) is extremely rare in children and adolescent. PC is more often sporadic, but also it could be associated with germline mutations. The clinical features of primary hyperparathyroidism (PHPT) are nonspecific in children and adolescent, which delays the diagnosis for years. This case of PC in a pediatric patient, caused by germline heterozygous pathogenic variant in exon 1 of the CDC73 gene (c.70 G > T, p. Glu24Ter) is the first to be reported in Russia. Due to the rarity of pediatric parathyroid malignancy, the diagnosis of this endocrine neoplasm remains a challenge. The main difficulties that we faced in the management of the patient were the morphological confirmation of diagnosis, multiple surgical interventions, and disseminated PC metastases. We describe a 13-year-old girl with delayed diagnosis of PC and subsequent local recurrence after several surgeries, who underwent specific radiation therapy that allowed controlling hypercalcemia.

Bisphosphonate-Induced Orbital Cellulitis in a Patient With Suspected Parathyroid Carcinoma: A Case Report.

Bisphosphonates are widely used for a number of metabolic bone conditions. Orbital inflammation is a very rare side effect of bisphosphonate therapy that can risk permanent visual loss. We describe the complex case and successful treatment of a 79-year-old man who developed orbital cellulitis following the use of intravenous pamidronate disodium for severe hypercalcaemia. The challenges regarding the diagnosis of parathyroid carcinoma are also discussed.

Incidental synchronous intrathyroidal parathyroid carcinomas and papillary thyroid microcarcinoma with compressive neck mass and primary hyperparathyroidism: case report and literature review.

BACKGROUND: Parathyroid carcinoma (PC) is a rare malignancy, often diagnosed incidentally through postoperative pathological examination. The occurrence of nodular goiter, intrathyroidal parathyroid carcinoma, contralateral parathyroid adenoma (PA), and papillary thyroid microcarcinoma (PTMC) is extremely uncommon, which prompted us to report our case experience. CASE PRESENTATION: We describe a 67-year-old male who presented with a cervical mass causing tracheal compression, which prompted him to seek medical advice. Based on preoperative auxiliary examination results from color Doppler ultrasound, SPECT parathyroid imaging, and blood tests, he was initially diagnosed with a suspected parathyroid adenoma and nodular goiter. Excision of the right lobe and isthmus of the thyroid, and left superior parathyroid gland was conducted, which were sent to intraoperative frozen pathological examination. During intraoperative observation, adhesion around the right thyroid lobe was discovered. Consequently, right central area lymph node dissection was performed due to suspicion of an aggressive malignant tumor. Histology and immunohistochemistry analysis revealed incidental intrathyroidal parathyroid carcinoma, contralateral parathyroid adenoma, classical papillary thyroid microcarcinoma, and nodular goiter. CONCLUSION: Parathyroid carcinoma should be highly suspected when extremely high levels of PTH and severe hypercalcemia are present, which cannot be simply explained by a preoperatively localized parathyroid adenoma, especially when suspicious malignant adhesion is found during intraoperative exploration. In cases where multifocal thyroid nodules are associated with increased uptake of 99Tc-sestamibi, the possibility of coexisting carcinomas should be considered, not only for thyroid malignancy but also for the potential presence of intrathyroidal parathyroid carcinoma.

Imaging Recommendations for Diagnosis and Management of Primary Parathyroid Pathologies: A Comprehensive Review.

Parathyroid pathologies are suspected based on the biochemical alterations and clinical manifestations, and the predominant roles of imaging in primary hyperparathyroidism are localisation of tumour within parathyroid glands, surgical planning, and to look for any ectopic parathyroid tissue in the setting of recurrent disease. This article provides a comprehensive review of embryology and anatomical variations of parathyroid glands and their clinical relevance, surgical anatomy of parathyroid glands, differentiation between multiglandular parathyroid disease, solitary adenoma, atypical parathyroid tumour, and parathyroid carcinoma. The roles, advantages and limitations of ultrasound, four-dimensional computed tomography (4DCT), radiolabelled technetium-99 (99mTc) sestamibi or dual tracer 99mTc pertechnetate and 99mTc-sestamibi with or without single photon emission computed tomography (SPECT) or SPECT/CT, dynamic enhanced magnetic resonance imaging (4DMRI), and fluoro-choline positron emission tomography (18F-FCH PET) or [11C] Methionine (11C -MET) PET in the management of parathyroid lesions have been extensively discussed in this article. The role of fluorodeoxyglucose PET (FDG-PET) has also been elucidated in this article. Management guidelines for parathyroid carcinoma proposed by the American Society of Clinical Oncology (ASCO) have also been described. An algorithm for management of parathyroid lesions has been provided at the end to serve as a quick reference guide for radiologists, clinicians and surgeons.

Dual-Tracer Positron Emission Tomography/Computed Tomography with [18F]FDG and [18F]fluorocholine in a Patient with Metastatic Parathyroid Carcinoma.

Here, we describe the case of a 43-year-old male patient with a metastatic parathyroid carcinoma who underwent dual-tracer whole-body positron emission tomography/computed tomography (PET/CT) with [18F]fluorocholine and fluorodeoxyglucose ([18F]FDG) for staging. [18F]FDG PET/CT detected multiple cervical and mediastinal lymph nodal lesions with increased tracer uptake, whereas [18F]fluorocholine PET/CT detected increased tracer uptake on cervical and mediastinal lymph nodal lesions and bone and lung lesions with a better evaluation of metastatic spread. Due to these imaging findings, the patient underwent systemic treatment with chemotherapy. This case demonstrates the added value of dual-tracer PET/CT in this rare metastatic tumor.

Parathyroid carcinoma located in the thyroid gland: A case report.

BACKGROUND: Parathyroid carcinoma (PC) is a difficult-to-diagnose rare disease with low incidence. Relatively accurate preoperative diagnosis is very important in choosing surgical methods and patient prognosis. CASE SUMMARY: This study reported the clinical diagnosis and treatment of a rare patient with PC located in the thyroid gland and provided a case reference for the diagnosis and treatment of PC. A case of a 64-year-old male patient who presented to our hospital with systemic muscle and joint pain and palpitations is outlined. Subsequently, the patient was admitted to the Department of Nephrology for the treatment of "multiple myeloma nephropathy pending investigation". The patient was diagnosed with "primary hyperparathyroidism and hypercalcemic crisis" using thyroid color ultrasound. CONCLUSION: The intraoperative frozen section report considered the parathyroid tumor. Surgical tumor resection was promptly performed, and the diagnosis of PC was confirmed.

Refractory Hypercalcemia Secondary to Metastatic Parathyroid Carcinoma Treated With Immunotherapy.

Parathyroid carcinoma (PC) is a rare endocrine malignancy and an uncommon cause of primary hyperparathyroidism. Metastatic disease confers a guarded prognosis with limited systemic treatment options available. We describe a case of a 64-year-old woman with primary hyperparathyroidism secondary to PC. Despite initial surgical resection, the patient relapsed within 6 months with widespread cerebral and skeletal metastatic disease. She developed worsening parathyroid hormone-mediated hypercalcemia that was refractory to escalating doses of cinacalcet and antiresorptive therapy. Molecular genomics identified high tumor mutation burden within the malignant tissue and single-agent nivolumab immunotherapy was administered. After one dose, there was resolution of her refractory hypercalcemia and primary hyperparathyroidism. The patient has tolerated ongoing treatment with 3 weekly cycles of nivolumab. She remains in biochemical remission as of June 2024, which is now 12 months after commencement of nivolumab.

Advances in the management of parathyroid carcinoma.

Parathyroid carcinoma (PCA) is a rare malignancy accounting for approximately 1% of all patients with primary hyperparathyroidism. It is characterised by excessive parathyroid hormone (PTH) production. This manuscript reviews recent advances in the management of parathyroid carcinoma, focusing on molecular insights, diagnostic modalities, surgical innovations, adjuvant therapies, and emerging targeted treatments. Recently published manuscripts (between 2022 and 2023) were obtained from Medical Literature Analysis and Retrieval System Online (Medline), Excerpta Medica (Embase), Cochrane Central Register of Controlled Trials (CENTRAL), and European Union Drug Regulating Authorities Clinical Trials (EudraCT). These were assessed for their relevance in terms of the diagnosis and management of patients with PCA. This manuscript explores the role of genetic profiling and presents case studies illustrating successful management strategies. The manuscript also discusses the ongoing challenges in the management of parathyroid carcinoma, suggesting future research directions and potential therapeutic avenues.

Long-term survival in a patient with metastatic parathyroid carcinoma harboring an EGFR sensitizing mutation: a case report.

Parathyroid carcinoma (PC) is a rare and aggressive endocrine malignancy with limited treatment options. Current treatments such as chemotherapy and radiotherapy have demonstrated limited efficacy. Here, we report the case of a male patient who presented with symptoms including polydipsia, polyuria, and joint pain. Further examination revealed a neck lump, hypercalcemia, and hyperparathyroidism, leading to a diagnosis of PC after en bloc surgery. Seven months later, the patient developed local recurrence and lung metastases, which were resected via left lateral neck dissection and thoracoscopic wedge resection. A 422-gene panel test revealed the presence of epidermal growth factor receptor (EGFR) p.L858R (c. T2573G) mutation, which may sensitize the EGFR-tyrosine kinase inhibitor response, and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) p.E545KV (c. G1633A) mutation. After multidisciplinary treatment discussions, the patient was treated with the multi-target tyrosine kinase inhibitor, anlotinib, resulting in survival benefits for 19 months. This case highlights the potential of targeted therapy in terms of long-term survival in patients with distant metastatic PC, as well as the importance of precision therapy guided by genome sequencing to identify potential therapeutic targets.

Sporadic Parathyroid Carcinoma Treated With Lenvatinib, Exhibiting a Novel Somatic MEN1 Mutation.

Parathyroid carcinoma (PC) is extremely rare and is primarily treated surgically. Chemotherapy is an option for advanced stages, but no standard regimen exists. Emerging research suggests the efficacy of multitarget tyrosine kinase inhibitors (MTKIs) for PC, targeting vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR). A 61-year-old Japanese woman presented with a neck mass, diagnosed as PC with pleural and lumbar metastases. After parathyroidectomy and radiation for lumbar metastasis, immunohistochemistry showed VEGFR overexpression, leading to targeted therapy with MTKIs. Despite no actionable mutations on cancer genomic panel test, a novel MEN1 somatic mutation (NM_130801: exon2: c.332delG: p.G111fs*8) was identified, which may affect VEGFR2 expression and tumor epigenetics. Although severe hand-foot syndrome necessitated dose reductions and treatment interruptions, sorafenib treatment managed hypercalcemia with evocalcet and denosumab. Lenvatinib, as second-line therapy, was effective against pleural metastases but caused thrombocytopenia and hematuria, leading to discontinuation and uncontrolled recurrence and metastasis progression. Our case highlights the need for further research on genomic profiling, molecular targets, and therapy response in PC.

[The role of immunohistochemical examination in the differential diagnosis of atypical tumors and carcinomas of parathyroid glands]. / Rol' immunogistokhimicheskogo analiza v differentsial'noi diagnostike atipicheskikh opukholei i kartsinom okoloshchitovidnykh zhelez.

Differential diagnosis of atypical parathyroid tumors (APT) and parathyroid carcinomas (PC) is important in determining further management and prognosis. Morphologic diagnosis is sometimes difficult, in which case it is supplemented by immunohistochemical (IHC) examination. OBJECTIVE: Studying the role of IHC analysis in the differential diagnosis of APT and PC. MATERIAL AND METHODS: The study included 44 patients with morphologic diagnosis of the APT established after surgical treatment for primary hyperparathyroidism on the basis of Endocrinology Research Centre during 2018-2023. All cases underwent IHC examination with evaluation of CD31/CD34 and parathormone (PTH) expression for identification of vascular invasion, Ki-67, parafibromin. RESULTS: According to the results of IHC analysis in 8/44 patients (18.2%) the diagnosis of APT was revised in favor of the PC: in 7 of them vascular invasion was detected; in 1 patient the additional series of slices in the surrounding fatty tissue revealed foci of tumor growth, confirmed by positive reaction with antibodies to PTH. According to IHC results, the material was divided into 2 groups: APT and PC. There were no differences in clinical and morphological characteristics, Ki-67% level and parafibromin expression between the groups. CONCLUSION: Assessment of clinical and laboratory-instrumental data at the preoperative stage does not allow differentiating APT from PC. In case of APT diagnosis and detection of suspicious morphological features, it is necessary to perform IHC examination to exclude PC.

Clinicopathological spectrum, management, and outcome of ectopic parathyroid carcinoma: Experience with 24 cases.

PURPOSE: Ectopic parathyroid carcinoma (EPC) is a rare clinical entity with multiple diagnostic pitfalls, making surgical cures challenging. We assessed the clinicopathological spectrum and outcome of EPCs. METHODS: In this retrospective cohort study, 24 EPCs were identified from 133 PC patients treated at a tertiary referral center. The relationship between clinicopathological findings and locations was analyzed. RESULTS: The locations of EPCs were predominantly intrathyroidal (62.5%), followed by 16.7% in the mediastinum, 8.3% in the retropharyngeal space, 8.3% in the carotid sheath, and 4.2% in the upper neck. Intrathyroidal EPC patients experienced higher serum calcium (p = 0.020), a higher rate of vascular invasion (p = 0.040), and a slightly higher incidence of non-R0 initial resection (p = 0.092) than those in other ectopic locations. Intrathyroidal EPC patients also suffered a trend of higher upper aerodigestive tract (UAT) invasion rate (p = 0.070) and higher risks of distant metastasis (p = 0.037) than the other PC patients. The 5-year disease-free survival rate after surgery was slightly compromised at 41.5% in intrathyroidal EPC patients compared with 77.8% among those in other ectopic locations (p = 0.143) and 59.7% among the other PC patients (log-rank = 3.194; p = 0.074), though without statistical significance. CONCLUSION: Intrathyroidal EPC might cause a more biochemically and invasively distinct PC picture compared with other PCs. Special caution should be exercised in the preoperative diagnosis and management of such cases.

Acute pancreatitis and refractory hypercalcemia in the third trimester caused by parathyroid carcinoma.

BACKGROUND: Hypercalcemia can be a rare contributor to acute pancreatitis (AP) in pregnancy. This is primarily due to primary hyperparathyroidism (PHPT), resulting from parathyroid carcinoma. We exhibited a case report to analyze the diagnosis and treatment during the onset of hypercalcemia-induced AP. CASE PRESENTATION: A 32-year-old primigravida presented with acute pancreatitis near full-term gestation. Following a cesarean delivery, there was a reduction in serum amylase and peripancreatic exudate, but her serum calcium concentrations persistently elevated over 4.0 mmol/L. Interventions to lower the hypercalcemia were only temporarily effective, until a high serum parathyroid hormone (PTH) concentration of 1404 pg/mL was detected. Ultrasound revealed a 31 mm × 24 mm hypoechoic oval nodule in the left lower lobe of the thyroid gland. She underwent a parathyroidectomy, resulting in a dramatic decrease in serum PTH level, from preoperative levels of 2051 pg/mL to 299 pg/mL just 20 minutes after removal. Similarly, her serum calcium declined from 3.82 mmol/L to 1.73 mmol/L within 24 hours postoperatively. The final histopathology suggested parathyroid carcinoma. CONCLUSION: When refractory hypercalcemia is present, serum PTH levels should be measured to determine PHPT. Parathyroidectomy is the optimal strategy for alleviating hypercalcemia and clarifying the underlying pathology.

Coincidence or Causality: Parathyroid Carcinoma in Chronic Kidney Disease-Case Report and Literature Review.

Parathyroid carcinoma (PC) associated with primary hyperparathyroidism (PHPT) has been well investigated in recent years. Data regarding PC evolution in secondary hyperparathyroidism (SHPT) due to chronic kidney disease (CKD) are, however, scarce. Most features that raise the suspicion of PC in PHPT are part of the usual SHPT evolution in CKD, mirroring the natural changes undergone by the parathyroid glands. Therefore, pre-surgically establishing the malignant or benign character of the lesions is cumbersome. We present two cases of PC in end-stage renal disease, one of which was bilateral, diagnosed after total parathyroidectomy in a high-volume parathyroid surgery center. A literature review of the data was also performed. A systematic search of the PubMed/MEDLINE database until January 2024 identified 42 cases of PC associated with SHPT. Understanding the PC features in CKD might improve associated bone and mineral disease management, and reduce the risk of metastasis, parathyromatosis, or recurrence. Irradiation, prolonged immunosuppression, long dialysis vintage, and genotype may predispose to the malignant transformation of chronically stimulated parathyroids. Despite postsurgical diagnosis, favorable outcomes occurred when distant metastases were absent, even without "en bloc" resection. Further research is warranted to delineate specific diagnostic and therapeutic approaches tailored to this particular patient subpopulation.

Whole-exome sequencing of atypical parathyroid tumors detects novel and common genes linked to parathyroid tumorigenesis.

CONTEXT: Atypical parathyroid tumor (APT) represents a neoplasm characterized by histological features typical of parathyroid carcinoma (PC) but lacking local infiltration and/or distant metastasis, leading to uncertainty regarding its malignant potential. OBJECTIVE: To characterize the molecular landscape and deregulated pathways in APT. METHODS: Whole exome sequencing (WES) was conducted on 16 APTs. DNA from tumors and matched peripheral blood underwent WES using Illumina HiSeq3000. RESULTS: A total of 192 nonsynonymous variants were identified. The median number of protein-altering mutations was 9. The most frequently mutated genes included BCOR, CLMN, EZH1, JAM2, KRTAP13-3, MUC16, MUC19, and OR1S1. Seventeen mutated genes belong to the Cancer Gene Census list. The most consistent hub genes identified through STRING network analysis were ATM, COL4A5, EZH2, MED12, MEN1, MTOR, PI3, PIK3CA, PIK3CB, and UBR5. Deregulated pathways included the PI3 K/AKT/mTOR pathway, Wnt signaling, and extracellular matrix organization. Variants in genes such as MEN1, CDC73, EZH2, PIK3CA, and MTOR, previously reported as established or putative/candidate driver genes in benign adenoma (PA) and/or PC, were also identified in APT. CONCLUSIONS: APT does not appear to have a specific molecular signature but shares genomic alterations with both PA and PC. The incidence of CDC73 mutations is low, and it remains unclear whether these mutations are associated with a higher risk of recurrence. Our study confirms that PI3 K/AKT/mTOR and Wnt signaling represents the pivotal pathways in parathyroid tumorigenesis and also revealed mutations in key epigenetic modifier genes (BCOR, KDM2A, MBD4, and EZH2) involved in chromatin remodeling, DNA, and histone methylation.

The prognostic value of lymph node dissection in patients with parathyroid carcinoma.

Background: Surgery is the only curative treatment strategy for parathyroid carcinoma (PC). However, the optimal extent of surgery remains uncertain, particularly regarding whether routine central lymph node dissection (LND) confers a survival advantage to patients with PC. This study aimed to evaluate the prognostic value of LND in PC patients. Methods: Patients diagnosed with PC between 2004 and 2018 were identified in the Surveillance, Epidemiology, and End Results (SEER)-18 registries. With inclusion and exclusion criteria, a total of 338 patients were included as cohort 1 to describe the characteristics of PC, while 215 patients were selected as cohort 2 to assess the effect of LND on cancer-specific survival (CSS). Univariate and multivariate Cox proportional hazards regression models were used to identify independent risk factors associated with CSS. Propensity score matching (PSM) was performed to adjust for potential confounding variables. The prognostic value of LND was further analyzed in subgroups stratified by predictors associated with CSS. Results: The 5- and 10-year CSS were 94.4% and 87.9% respectively in cohort 1. LND failed to significantly improve CSS in the entire cohort 2 and the PSM cohort 2. Large tumor size (>40 mm) and distant metastasis were independently associated with poor CSS. Subgroup analyses revealed that LND was not significantly associated with improved CSS in patients with aggressive PC, such as those with a tumor size greater than 40 mm. Unexpectedly, LND may compromise CSS in patients with distant disease (P=0.03). Conclusions: PC is a rare and indolent endocrine malignancy. The presence of large tumors and distant metastases are independent predictors of poor CSS. Routine central LND as part of initial surgery does not significantly improve CSS in PC patients, even for those with large tumors, lymph node metastasis, or distant disease.

Parathyroid tumors in the 5th edition of the WHO Classification of Tumors of the Endocrine Organs.

The diagnosis of pathological conditions of the parathyroid glands is the answer to clinically more frequently detected hypercalcemic conditions, including MEN syndromes. In routine biopsy practice, enlarged bodies are also a differential diagnosis for the diagnosis of thyroid nodules. In the chapter of parathyroid tumors, the 5th edition of the WHO classification brings changes influenced similarly to other endocrine organs by the increase in genetic information. At the terminological level, the concept of hyperplasia has been narrowed down to secondary hyperplasia, most of the previously primary hyperplasias are referred to as multiglandular parathyroid disease due to evidence of multiglandular clonal proliferations. The term atypical parathyroid tumor replacing atypical adenoma is newly introduced - the uncertain biological behaviour is emphasized. The basic examination includes parafibromin immunohis- tochemistry, the deficiency of parafibromin being an indicator of an inactivating CDC73 mutation and an increased risk of familial forms, or MEN. Methodologically, refinements are introduced in the quantification of mitotic activity per 10 mm2. Oncocytic subtypes have an arbitrarily declared threshold of more than 75% oncocytes. The definition of lipoadenoma (multiplication of both components, more than 50% of adipose tissue in the tumor) is similarly specified. The diagnosis of cancer remains histopathological with unequivocal evidence of invasion, or microscopically verified metastasis.

Detection and identification of circulating tumor cells in parathyroid tumors and correlation analysis with clinicopathological features.

INTRODUCTION: The differential diagnosis of parathyroid carcinoma (PC)/parathyroid adenoma (PA) in parathyroid tumors is critical for their management and prognosis. Circulating tumor cells (CTCs) identification in the peripheral blood of parathyroid tumors remains unknown. In this study, we proposed to investigate the differences of CTCs in PC/PA and the relationship with clinicopathologic features to assess its relevance to PC and value in identifying PC/PA. METHODS AND MATERIALS: Peripheral blood was collected from 27 patients with PC and 37 patients with PA treated in our hospital, and the number of chromosome 8 aberrant CTCs was detected by negative magnetic bead sorting fluorescence in situ hybridization (NE-FISH). The differences of CTCs in PC/PA peripheral blood were compared and their diagnostic efficacy was evaluated, and the correlation between CTCs and clinicopathological features of PC was further explored. RESULTS: CTCs differed significantly in PC/PA (p = 0.0008) and were up-regulated in PC, with good diagnostic efficacy. CTCs combined with alkaline phosphatase (ALP) assay improved the diagnostic efficacy in identifying PC/PA (AUC = 0.7838, p = 0.0001). The number of CTCs was correlated with tumor dimensions, but not significantly correlated with clinical markers such as calcium and PTH and pathological features such as vascular invasion, lymph node metastasis and distant metastasis. CONCLUSION: As a non-invasive liquid biopsy method, CTCs test combined with ALP test can be used as an important reference basis for timely and accurate identification and treatment of PC. It is of great significance to improve the current situation of PC diagnosis, treatment and prognosis.

A case report of mediastinal parathyroid carcinoma in a chronic kidney disease patient: Addressing management conundrum.

Parathyroid carcinoma is a rare malignancy; and it is rarer to find one located in an ectopic location. Ectopic parathyroid glands are a reported cause of failed primary surgery for hyperparathyroidism. We report here a 73-year-old male who previously had parathyroidectomy for primary hyperparathyroidism but then had recurrence of his symptoms with a diagnosis of a mediastinal parathyroid carcinoma on further evaluation. This presentation of complicated mediastinal parathyroid carcinoma posed significant diagnostic and management challenges due to comorbid stage IV chronic kidney disease (CKD). Secondly, due to the same comorbid condition, a more aggressive calcimimetic regimen could not be undertaken due to the risk of renal dysfunction with potential progression to dialysis status. Thirdly, he was a high-risk surgical candidate due to significant cardiovascular risks. Ideally, open surgical intervention would be recommended but due to the associated risks, he was managed with robotic-assisted thoracoscopic surgery. He subsequently developed hypocalcemia which normalized with supplemental calcium at follow-up.

Cervicomediastinal Hematoma: Atypical Presentation of a Parathyroid Carcinoma.

Parathyroid carcinoma (PC) is a rare endocrine neoplasm that typically presents with osteopenia/osteoporosis, nephrolithiasis, asthenia, and neuropsychiatric symptoms. We describe the case of a 48-year-old woman, presenting with a large painful hematoma in the cervicomediastinal area. The neck ultrasound (US) demonstrated a solid lesion measuring 40 × 80 × 55 mm, markedly hypoechoic, which extended from the right thyroid lobe to the mediastinum. The blood tests showed elevated serum calcium and parathyroid hormone (PTH) concentrations, consistent with hypercalcemic primary hyperparathyroidism. The patient was rehydrated and treated with furosemide, cholecalciferol, and bisphosphonate, and underwent right lower parathyroidectomy, right hemithyroidectomy, and lymphadenectomy of the right VI cervical level. Histological examination was diagnostic for nonangioinvasive or neuroinvasive PC, and the thyroid lobe was the site of lymphocytic thyroiditis; all removed lymph nodes were benign. The postoperative course was regular. Postoperative neck US showed a hypoechoic left thyroid lobe without evidence of residual neoplasm in the right thyroid bed. Levothyroxine therapy of 50 mcg/day was started because of serum thyrotropin concentrations elevated at 18 mcIU/mL (normal reference range, 0.35-4.0 mIU/mL). Eight years after diagnosis, the patient is in good general condition, with no clinical, biochemical, or imaging evidence of disease persistence/recurrence.